OBRABOTKAMETALLOV Vol. 24 No. 2 2022 TECHNOLOGY Deformations in the nonstationary stage of aluminum alloy rod extrusion process with a low elongation ratio Yuri Loginov 1, 2, a,*, Georgy Shimov 1, b, Natalia Bushueva 1, c 1 Ural Federal University, 19 Mira st., Ekaterinburg, 620002, Russian Federation 2 M.N. Miheev Institute of Metal Physics of Ural Branch of RAS, 18 S. Kovalevskaya st., Ekaterinburg, 620137, Russian Federation a https://orcid.org/0000-0002-7222-2521, j.n.loginov@urfu.ru, b http://orcid.org/0000-0001-5763-0837, g.v.shimov@urfu.ru, c https://orcid.org/0000-0002-0603-8785, m0rgondagen@yandex.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2022 vol. 24 no. 2 pp. 39–49 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2022-24.2-39-49 ART I CLE I NFO Article history: Received: 21 март 2022 Revised: 21 April 2022 Accepted: 29 April 2022 Available online: 15 June 2022 Keywords: Extrusion process Metal forming Aluminum alloy Finite element method Plastic deformation Funding The study was fi nancially supported by the Russian Science Foundation, agreement 22-29-00931 dated December 20, 2021. Acknowledgements Research were partially conducted at core facility “Structure, mechanical and physical properties of materials” ABSTRACT Introduction. It is noted that extrusion is the main procurement process in the aluminum alloys forming operations. At the same time, the process has such a disadvantage as the nonstationarity of the metal plastic fl ow. The work aim is to establish the inhomogeneity deformation level of the pressed rod front part by numerical simulation using the fi nite element method. The study objectives are to formulate the extrusion process boundary conditions, to obtain a solution and to evaluate the inhomogeneity degree. Research methods: the fi nite element method was used to evaluate the deformed state. The actions sequence included the creation of primary deformation zone shape and the tool confi guration. The mutual movement of the tool and the deformable material is set using the appropriate boundary conditions. The deformable medium is a ductile material with power-law hardening, the physical and mechanical properties correspond to the aluminum alloy of the 6000 series. Results and discussion: It is revealed that the strain degree in the pressed rod front part is extremely nonuniform distributed; differences above 300% are recorded. The strain degree distribution dependences in the rod cross sections are constructed depending on the distance from the front end at different relative radial coordinates. It is revealed that the rod central layers acquire a constant level of the strain degree earlier than the peripheral layers. The stationary process is achieved with less metal motion. The work result application scope is the technological study of rational metal cutting of aluminum alloys at the extrusion fi nal stage in order to use recyclable waste more rationally. Conclusions. In the extrusion process with a low elongation ratio, the strain degree is distributed nonuniform both along the press rod cross and along its length. The rod front part remains weakly deformed both at the periphery and in the center in the nonstationary initial extrusion stage. It often forces to send for remelting due to the insuffi ciently developed metal structure. At the same time, if the limits on the minimum possible degree of deformation are set, then using the results of the calculation by the fi nite element method, the minimum length of the metal to be removed can be set, thereby reducing the mass of waste sent for remelting. For citation: Loginov Yu.N., Shimov G.V., Bushueva N.I. Deformations in the nonstationary stage of aluminum alloy rod extrusion process with a low elongation ratio. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2022, vol. 24, no. 2, pp. 39–49. DOI: 10.17212/1994-6309-2022-24.2-39-49. (In Russian). ______ * Corresponding author Loginov Yuri N., Ph.D. (Engineering), Full Professor Ural Federal University, 19 Mira st., 620002, Ekaterinburg, Russian Federation Tel.: 8 (343) 375-44-37, e-mail: j.n.loginov@urfu.ru Introduction Extrusion is one of the main procurement types of forming in the production of semi-fabricated products from aluminum and its alloys along with hot sheet rolling [1, 2]. The process is characterized by increased fl exibility: it is often enough to apply a die change for re-conversion. Such speed will not be achieved when using the rolling process, where whole rolls sets will have to be changed. Additionally, in the case
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